Composition and method for preparation of organic electronic devices

ABSTRACT

The present invention relates to novel compositions comprising an organic semiconductor (OSC) and one or more organic solvents. The composition is solid at a temperature of 25° C. and fluid at a higher temperature and the boiling point of the solvent is at most 400° C. Furthermore, the present invention describes the use of these compositions as inks for the preparation of organic electronic (OE) devices, especially organic photovoltaic (OPV) cells and OLED devices, to methods for preparing OE devices using the novel compositions, and to OE devices, OLED devices and OPV cells prepared from such methods and compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application (under 35 U.S.C. §371)of PCT/EP2011/001682, filed Apr. 5, 2011, which claims benefit ofEuropean application 10003857.9, filed Apr. 12, 2010.

FIELD OF THE INVENTION

The present invention relates to novel compositions comprising anorganic semiconducting compound (OSC), to their use as conducting inksfor the preparation of organic electronic (OE) devices, especiallyorganic photovoltaic (OPV) cells and OLED devices, to methods forpreparing OE devices using the novel formulations, and to OE devices andOPV cells prepared from such methods and compositions.

BACKGROUND AND PRIOR ART

When preparing OE devices like OFETs or OPV cells, in particularflexible devices, usually printing or coating techniques like inkjetprinting, roll to roll printing, slot dye coating orflexographic/gravure printing are used to apply the OSC layer. Based onlow solubility of the most of the present organic compounds useful asOSC these techniques need the use of solvents in high amounts. In orderto reduce solvent de-wetting and to increase dry film levelnesssurfactants can be used. These additives are especially needed withregard to small molecular OSC or polymeric OSC having a low molecularweight. The use of conventional surfactants or wetting agents isdisclosed, e.g. in WO 2009/049744. However, no explicit examples arementioned. Based on the low solubility of the most of the OSC materialsthe amounts of surfactants needed are high in relation to the amount ofOSC material in the ink formulation.

Furthermore, WO 2009/109273 describes compositions comprising specialsolvents in order to achieve specific viscosity. The specific viscosityis needed to apply the composition via application methods as roll toroll printing, slot dye coating or flexographic/gravure printing etc.without the need of using high amounts of polymeric binder. However,according to some embodiments of these compositions, these binders canbe used as optional components. In addition thereto, the compositionsmay comprise wetting agents as mentioned above.

Moreover, JP 2001-288416 discloses a coating liquid compositiondissolved or dispersed in at least two organic solvents comprising aliquid solvent and a solid solvent. Using a combination of a liquidsolvent and a solid solvent provides a thin film having a functionalmaterial in a highly dispersed isotropic state.

The OE devices as disclosed in WO 2009/049744, WO 2009/109273 and JP2001-288416 show useful efficiencies and lifetimes. However, it is apermanent desire to improve the performance of the OSC layer, such asefficiency, lifetime and sensitivity regarding oxidation or water.

In addition thereto, the formation of films having a high leveling isdifficult without the use of high amounts of wetting agents. However,these wetting agents may have some drawbacks regarding the performanceof the films formed.

Furthermore, the production of multilayer devices based on thetechnology as mentioned above is difficult to achieve. In order to applyan additional layer on an existing layer, generally the compositionsubsequently applied comprises a solvent which does not dissolve theexisting film. Such approach is usually called orthogonal solventapproach. However, if the organic semiconducting compounds of theexisting film and the semiconducting compounds of the subsequentlyapplied composition have similar properties and are soluble in similarsolvents such approach is difficult to achieve.

It is therefore desirable to have improved compositions comprising anOSC that are suitable for the preparation of OE devices, especially thinfilm transistors, diodes, OLED displays and OPV cells, which allow themanufacture of high efficient OE devices having a high performance, along lifetime and a low sensitivity against water or oxidation. One aimof the present invention is to provide such improved compositions.Another aim is to provide improved methods of preparing an OE devicefrom such compositions. Another aim is to provide improved OE devicesobtained from such compositions and methods. In particular, another aimis to provide improved methods for preparing multilayer devices. Furtheraims are immediately evident to the person skilled in the art from thefollowing description.

Surprisingly it has been found that these aims can be achieved, and theabove-mentioned problems can be solved, by providing methods, materialsand devices as claimed in the present invention, especially by providinga process for preparing an OE device using a composition being solid ata temperature of 25° C. and fluid at a higher temperature and theboiling point of the solvent is at most 400° C.

SUMMARY OF THE INVENTION

The present invention relates to a composition comprising one or moreorganic semiconducting compounds (OSC), and one or more organicsolvents, characterized in that said composition is solid at atemperature of 25° C. and fluid at a higher temperature and the boilingpoint of the solvent is at most 400° C.

The present invention further relates to the use of a composition asdescribed above and below as coating or printing ink, especially for thepreparation of OE devices, in particular for thin film transistors,diodes, OLED devices and rigid or flexible organic photovoltaic (OPV)cells and devices.

The present invention further relates to a process of preparing anorganic electronic (OE) device, comprising the steps of

-   a) depositing the composition as described above and below onto a    substrate to form a film or layer,-   b) removing the solvent(s).

The present invention further relates to an OE device prepared from acomposition and/or by a process as described above and below.

The OE devices include, without limitation, organic field effecttransistors (OFET), integrated circuits (IC), thin film transistors(TFT), Radio Frequency Identification (RFID) tags, organic lightemitting diodes (OLED), organic light emitting transistors (OLET),electroluminescent displays, organic photovoltaic (OPV) cells, organicsolar cells (O—SC), flexible OPVs and O—SCs, organic laserdiodes(O-laser), organic integrated circuits (O—IC), lighting devices, sensordevices, electrode materials, photoconductors, photodetectors,electrophotographic recording devices, capacitors, charge injectionlayers, Schottky diodes, planarising layers, anti-static films,conducting substrates, conducting patterns, photoconductors,electrophotographic devices, organic memory devices, biosensors andbiochips.

According to a preferred embodiment, the present invention providesorganic light emitting diodes (OLED). OLED devices can for example beused for illumination, for medical illumination purposes, as signallingdevice, as signage devices, and in displays. Displays can be addressedusing passive matrix driving, total matrix addressing or active matrixdriving. Transparent OLEDs can be manufactured by using opticallytransparent electrodes. Flexible OLEDs are assessable through the use offlexible substrates.

The compositions, methods and devices of the present invention providesurprising improvements in the efficiency of the OE devices and theproduction thereof. Unexpectedly, the performance, the lifetime and theefficiency of the OE devices can be improved, if these devices areachieved by using a composition of the present invention. Furthermore,the composition of the present invention provides an astonishingly highlevel of film forming. Especially, the homogeneity and the quality ofthe films can be improved. In addition thereto, the present inventionenables better printing of multi layer devices.

A BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A exemplarily and schematically depicts a typical bottom gate(BG), top contact (TC) OFET device according to the present invention,comprising a substrate (1), a gate electrode (2), a layer of dielectricmaterial (3) (also known as gate insulator layer), an OSC layer (4), andsource and drain (S/D) electrodes (5), and an optional passivation orprotection layer (6).

FIG. 1B exemplarily and schematically depicts a typical bottom gate(BG), bottom contact (BC) OFET device according to the presentinvention, comprising a substrate (1), a gate electrode (2), adielectric layer (3), S/D electrodes (5), an OSC layer (4), and anoptional passivation or protection layer (6).

FIG. 2 exemplarily and schematically depicts a top gate (TG) OFET deviceaccording to the present invention, comprising a substrate (1), sourceand drain electrodes (5), an OSC layer (4), a dielectric layer (3), anda gate electrode (2), and an optional passivation or protection layer(6).

FIGS. 3 and 4 exemplarily and schematically depict typical and preferredOPV devices according to the present invention.

FIG. 5 depicts the transistor characteristic and the linear andsaturation mobility of the device.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a composition being solid at atemperature of 25° C. and fluid at a higher temperature. These type ofcoating compositions or printing inks can be called hot melt formulationbased on the fact that the application of such compositions is performedat temperatures above 25° C.

Preferably said composition is solid at a temperature of 30° C.,especially 35° C., particularly 40° C., more preferably 50° C. and mostpreferably 60° C. The higher the temperature at which the composition issolid the easier the printing can be fixed on the substrate. The termsolid means that the viscosity of the ink is very high such that thecomposition cannot be applied by usual printing techniques. Therefore, acomposition comprising a viscosity of at least 500 Pas at thetemperatures as mentioned above and below (especially 25° C.) isconsidered solid. The viscosity values are measured with a parallelplate rotational viscometer or rheometer (TA Instruments) at a shearrate of 500 s⁻¹, unless stated otherwise.

However, if the inks are solid at very high temperatures, these inksneed to be applied at very high temperatures. High processingtemperatures need special equipment and stable organic semiconductingcompounds. Based on such issues, the composition of the presentinvention is preferably fluid at a temperature of 200° C. or less,especially 150° C. or less, more preferably 120° C. or less, and mostpreferably 100° C. or less.

The term fluid means that the viscosity of the ink is in a range suchthat the composition can be processed by usual printing techniques asmentioned above and below. Therefore, a composition comprising aviscosity in the range of 0.1 to 2000 mPas at the temperatures asmentioned above and below (200° C., 150° C., 120° C. and 100° C.,respectively) is considered fluid. The viscosity values are measuredwith a parallel plate rotational viscometer or rheometer (TAInstruments) at a sheer rate of 500 s⁻¹, unless stated otherwise.

Preferably, the composition has a viscosity in the range of 0.25 to 100mPas, especially 1.0 to 40 mPas, more preferably in the range of 2.0 to20 mPas and most preferably in the range of 2.1 to 15 mPas. Theviscosity is determined at a shear rate of 500 s⁻¹ by measuring on AR-G2rheometer manufactured by TA Instruments. This is measured usingparallel plate geometry. The temperature to determine the viscosity ispreferably about 10° C. above the melting point of the solvent havingthe highest boiling point. If merely fluid solvents are used, theviscosity can be determined at a processing temperature of thecomposition. Preferably, the composition of the present inventioncomprises a surface tension in the range of 20 to 60 mN/m, morepreferably 25 to 45 mN/m. The surface tension can be measured using aFTA (First Ten Angstrom) 125 contact angle goniometer as mentioned aboveand below. The surface tension can be achieved by selection thepolymeric binder and the solvent in an appropriate manner. Furthermore,the surface tension can be achieved by using a wetting agent, preferablya volatile wetting agent as mentioned below. The temperature todetermine the surface tension is preferably about 10° C. above themelting point of the solvent having the highest boiling point.

Preferably, the composition can be filtered e.g. to 1 micron or less.

The composition of the present invention comprises one or more solvents.The solvents are preferably selected from the group consisting ofaromatic hydrocarbons, like toluene, o-, m- or p-xylene,trimethylbenzenes (e.g. 1,2,3-, 1,2,4- and 1,3,5-trimethylbenzenes),tetralin, other mono-, di-, tri- and tetraalkylbenzenes (e.g.diethylbenzenes, methylcumene, tetramethylbenzenes etc), aromatic ethers(e.g. anisole, alkylanisoles, e.g. 2, 3 and 4 isomers of methylanisole,2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-isomers of dimethylanisole),naphthalene derivatives, alkylnaphthalene derivatives (e.g. 1- and2-methylnaphthalene), di- and tetrahydronaphthalene derivatives. Alsopreferred are aromatic esters (e.g alkylbenzoates), aromatic ketones(e.g. acetophenone, propiophenone), alkylketones (e.g. cyclohexanone),aromatic ketones (e.g benzophenone), heteroaromatic solvents (e.g.thiophene, mono-, di- and trialkylthiophenes, 2-alkyl-thiazoles,benzthiazoles etc, pyridines), halogenaryls and aniline derivatives.These solvents may comprise halogen atoms.

Especially preferred are: 3-fluorotrifluoromethylbenzene,trifluoromethyl-benzene, dioxane, trifluoromethoxybenzene,4-fluorobenzenetrifluoride, 3-fluoropyridine, toluene, 2-fluorotoluene,2-fluorobenzenetrifluoride, 3-fluorotoluene, pyridine, 4-fluorotoluene,2,5-difluorotoluene, 1-chloro-2,4-difluorobenzene, 2-fluoropyridine,3-chlorofluorobenzene, 1-chloro-2,5-difluorobenzene,4-chlorofluorobenzene, chlorobenzene, 2-chlorofluorobenzene, p-xylene,m-xylene, o-xylene, 2,6-lutidine, 2-fluoro-m-xylene, 3-fluoro-o-xylene,2-chlorobenzenetrifluoride, dimethylformamide, 2-chloro-6-fluorotoluene,2-fluoroanisole, anisole, 2,3-dimethylpyrazine, bromobenzene,4-fluoroanisole, 3-fluoroanisole, 3-trifluoromethylanisole,2-methylanisole, phenetol, benzenedioxol, 4-methylanisole,3-methylanisole, 4-fluoro-3-methylanisole, 1,2-dichlorobenzene,2-fluorobenzene-nitril, 4-fluoroveratrol, 2,6-dimethylanisole, aniline,3-fluorobenzenenitril, 2,5-dimethylanisole, 3,4-dimethylanisole,2,4-dimethylanisole, benzene-nitrile, 3,5-dimethylanisole,N,N-dimethylaniline, 1-fluoro-3,5-dimethoxybenzene, phenylacetate,N-methylaniline, methylbenzoate, N-methylpyrrolidone, morpholine,1,2-dihydronaphthalene, 1,2,3,4-tetrahydronaphthalene, o-tolunitrile,veratrole, ethylbenzoate, N,N-diethylaniline, propylbenzoate,1-methylnaphthalene, butylbenzoate, 2-methylbiphenyl, 2-phenylpyridineor 2,2′-Bitolyl.

In order to achieve a composition being solid at a temperature of 25° C.and fluid at a higher temperature one or more additives can be used.

According to a preferred embodiment of the present invention, solventscan be used being solid at 25° C. and fluid, preferably liquid at highertemperatures. Using these solvents provides astonishingly improvementsregarding the performance of the organic electronic devices beingobtained using the inventive compositions.

Preferably, the solvent is solid at a temperature of 25° C.,particularly of 30° C., especially of 35° C., particularly of 40° C.,more preferably of 50° C. and most preferably of 60° C. The term solidis used as mentioned above with regard to the composition. Preferably,the solvent has a melting point at a temperature of 25° C. or above,particularly 30° C. or above, especially 35° C. or above, particularly40° C. or above, more preferably 50° C. or above and most preferably 60°C. or above.

Preferably the solvent is fluid at a temperature of 200° C. or less,especially 150° C. or less, more preferably 120° C. or less, and mostpreferably 100° C. or less. The term fluid is used as mentioned abovewith regard to the composition. According, the solvent has a meltingpoint at a temperature of 200° C. or less, especially 150° C. or less,more preferably 120° C. or less, and most preferably 100° C. or less.

These solvents are not specially limited and may include aliphaticcompounds such as alkanes and may comprise functional groups such ashydroxyl groups, carboxylic acid groups or halogens, if these solventsdo not react with the organic semiconducting compound. According to aspecial aspect of the present invention the organic solvent preferablycomprises an aromatic and/or heteroaromatic compound, especially anaromatic compound, and more preferably an aromatic hydrocarbon compound.In particular, the organic solvent may comprise a benzene compound, apyridine compound, a pyrazine compound, a pyrazole compound having amolecular weight of at least 120 g/mol, especially at least 130 g/moland more preferably at least 140 g/mol, a sulphone compound, a sulfolanecompound, an alcohol compound, and/or a naphthalene compound. Preferredbenzene compounds include, e.g. 1,2,4,5-tetramethylbenzene,pentamethylbenzene and hexamethylbenzene. Preferred naphthalenecompounds include, e.g. 2-methylnaphthalene, 1,5-dimethylnaphthalene and2-ethoxynaphthalene.

Astonishing improvements can be achieved by a mixture of organicsolvent. In particular the solvent mixture may comprise at least onebenzene compound, especially having a molecular weight of at least 120g/mol, especially at least 130 g/mol. Moreover specific mixtures maycomprise at least one naphthalene compound.

Examples of compounds useful as solvents are disclosed in Table 1.

TABLE 1 Melting and boiling points of useful solvents Melting pointBoiling point Solvent [° C.] [° C.] Sulfolane 27 2851,2,3,4-Tetrahydro-1-naphthalene 30 269 2-Methylnaphthalene (2-MN) 35241 2-Ethoxynaphthalene 36 282 2,3,4,6-Tetrachloropyridine 38 248 Benzylphenyl ether 40 287 Docosane 45 369 2,3,5-Trichloropyridine 48 219Pentamethylbenzene 50 231 Benzophenone 52 305 5-Indanol 52 2551,2,3-Trichlorobenzene 52 218 Pyrazine 53 1165,6,7,8-Tetrahydro-2-naphthalene 60 276 p-Bromochlorobenzene 66 196Di-isopropylnaphthalene 68 279 Pyrazole 68 187 Biphenyl 69 255 2-Indanol70 253 Stearic acid 70 361 2,6-Dichloronitrobenzene 71 2721,5-Dimethylnaphthalene (1,5-DMN) 77 265 1,2,4,5-Tetramethylbenzene 78197 Naphthalene 81 218 Pentachlorobenzene 86 277 Carbon tetrabromide 89190 Imidazole 90 256 3,5-Dimethylpyrazole 107 218 Dimethyl sulphone 108238 1,3,5-Tribromobenzene 120 271 Benzoic acid 123 249 Octachloropropane160 269 Hexamethylbenzene 165 264

These solvents can be used as mixture of two, three or more.

Preferably the solvent has a boiling point or sublimation temperature of<400° C., especially ≦350° C., more preferably ≦270° C., most preferably≦250° C., at the pressure employed, very preferably at atmosphericpressure (1013 hPa). Evaporation can also be accelerated e.g. byapplying heat and/or reduced pressure.

Preferably, the organic solvent can comprise a surface tension in therange of 15 to 80 mN/m, more preferably 25 mN/m to 45 mN/m. The surfacetension can be measured using a FTA (First Ten Angstrom) 125 contactangle goniometer. Details of the method are available from First TenAngstrom as published by Roger P. Woodward, Ph.D. “Surface TensionMeasurements Using the Drop Shape Method”. Preferably, the pendant dropmethod can be used to determine the surface tension. The temperature fordetermining the surface tension is preferably in the range of about 30°C. to 200° C., especially 60° C. to 150° C. and more preferably 80° C.to 120° C. According to a special aspect of the present invention, thesurface tension of the solvent can be determined at a temperature of 10°C. above the melting point of the solvent. If merely fluid solvents areused, the surface tension can be preferably determined at theapplication temperature.

Preferred organic solvents can comprise Hansen Solubility parameters ofH_(d) in the range of 17.0 to 23.2 MPa^(0.5), H_(p) in the range of 0.2to 12.5 MPa^(0.5) and H_(h) in the range of 0.9 to 14.2 MPa^(0.5). Morepreferred organic solvents comprise Hansen Solubility parameters ofH_(d) in the range of 18.5 to 21.0 MPa^(0.5), H_(p) in the range of 2.0to 6.0 MPa^(0.5) and H_(h) in the range of 2.0 to 6.0 MPa^(0.5).

The Hansen Solubility Parameters can be determined according to theHansen Solubility Parameters in Practice (HSPiP) program (2^(nd)edition) as supplied by Hanson and Abbot et al.

The composition of the present invention preferably comprises at least70% by weight, more preferably at least 80% by weight and mostpreferably at least 90% by weight of organic solvents.

The processing temperature used for removing the solvent and anyvolatile additive should be selected such that the layer, comprising theorganic semiconducting material, is not damaged. Preferably thedeposition processing temperature is from about 30° C. to 200° C., morepreferably 60° C. to 150° C. and most preferably 80° C. to 120° C.

The OSC compounds can be selected from standard materials known to theskilled person and described in the literature. The OSC may be amonomeric compound (also referred to as “small molecule”, as compared toa polymer or macromolecule), a polymeric compound, or a mixture,dispersion or blend containing one or more compounds selected fromeither or both of monomeric and polymeric compounds.

In one preferred embodiment of the present invention the OSC is selectedfrom monomeric compounds, where it is easier to achieve a significantvariation in the degree of crystallinity.

According to an aspect of the present invention, the OSC is preferably aconjugated aromatic molecule, and contains preferably at least threearomatic rings, which can be fused or unfused. Unfused rings areconnected e.g. via a linkage group, a single bond or a spiro-linkage.Preferred monomeric OSC compounds contain one or more rings selectedfrom the group consisting of 5-, 6- or 7-membered aromatic rings, andmore preferably contain only 5- or 6-membered aromatic rings. Thematerial may be a monomer, oligomer or polymer, including mixtures,dispersions and blends.

Each of the aromatic rings optionally contains one or more hetero atomsselected from Se, Te, P, Si, B, As, N, O or S, preferably from N, O orS.

The aromatic rings may be optionally substituted with alkyl, alkoxy,polyalkoxy, thioalkyl, acyl, aryl or substituted aryl groups, halogen,particularly fluorine, cyano, nitro or an optionally substitutedsecondary or tertiary alkylamine or arylamine represented by—N(R^(x))(R^(y)), where R^(x) and R^(y) independently of each otherdenote H, optionally substituted alkyl, optionally substituted aryl,alkoxy or polyalkoxy groups. Where R^(x) and/or R^(y) denote alkyl oraryl these may be optionally fluorinated.

Preferred rings are optionally fused, or are optionally linked with aconjugated linking group such as —C(T¹)=C(T²)-, —C≡C—, —N(R^(z))—,—N═N—, —(R^(z))C═N—, —N═C(R^(z))—, wherein T¹ and T² independently ofeach other denote H, Cl, F, —C≡N— or a lower alkyl group, preferably aC₁₋₄ alkyl group, and R^(z) denotes H, optionally substituted alkyl oroptionally substituted aryl. Where R^(z) is alkyl or aryl these may beoptionally fluorinated.

Preferred OSC compounds include small molecules (i.e. monomericcompounds), polymers, oligomers and derivatives thereof, selected fromcondensed aromatic hydrocarbons such as tetracene, chrysene, pentacene,pyrene, perylene, coronene, or soluble substituted derivatives of theaforementioned; oligomeric para substituted phenylenes such asp-quaterphenyl (p-4P), p-quinquephenyl (p-5P), p-sexiphenyl (p-6P), orsoluble substituted derivatives of the aforementioned; conjugatedhydrocarbon polymers such as polyacene, polyphenylene, poly(phenylenevinylene), polyfluorene, polyindenofluorene, including oligomers ofthese conjugated hydrocarbon polymers; conjugated heterocyclic polymerssuch as poly(3-substituted thiophene), poly(3,4-bisubstitutedthiophene), polyselenophene, poly(3-substituted selenophene),poly(3,4-bisubstituted selenophene), polybenzothiophene,polyisothianapthene, poly(N-substituted pyrrole), poly(3-substitutedpyrrole), poly(3,4-bisubstituted pyrrole), polyfuran, polypyridine,poly-1,3,4-oxadiazole, polyisothianaphthene, poly(N-substitutedaniline), poly(2-substituted aniline), poly(3-substituted aniline),poly(2,3-bisubstituted aniline), polyazulene, polypyrenepolybenzofuran;polyindole, polypyridazine, polytriarylamines such as optionallysubstituted polytriphenylamines; pyrazoline compounds; benzidinecompounds; stilbene compounds; triazines; substituted metallo- ormetal-free porphines, phthalocyanines, fluorophthalocyanines,naphthalocyanines or fluoronaphthalocyanines; C₆₀ and C₇₀ fullerenes orderivatives thereof; N,N′-dialkyl, substituted dialkyl, diaryl orsubstituted diaryl-1,4,5,8-naphthalenetetracarboxylic diimide and fluoroderivatives; N,N′-dialkyl, substituted dialkyl, diaryl or substituteddiaryl 3,4,9,10-perylenetetracarboxylic diimide; bathophenanthroline;diphenoquinones; 1,3,4-oxadiazoles;11,11,12,12-tetracyanonaptho-2,6-quinodimethane;α,α′-bis(dithieno[3,2-b:2′,3′-d]thiophene); 2,8-dialkyl, substituteddialkyl, diaryl or substituted diaryl anthradithiophene;2,2′-bibenzo[1,2-b:4,5-b]-dithiophene. Preferred compounds are thosefrom the above list and derivatives thereof which are soluble.

Especially preferred OSC materials are substituted polyacenes, such as6,13-bis(trialkylsilylethynyl)pentacene or derivatives thereof, such as5,11-bis(trialkylsilylethynyl)anthradithiophenes, as described forexample in U.S. Pat. No. 6,690,029, WO 2005/055248 A1, or WO 2008/107089A1. A further preferred OSC material is poly(3-substituted thiophene),very preferably poly(3-alkylthiophenes) (P3AT) wherein the alkyl groupis preferably straight-chain and preferably has 1 to 12, most preferably4 to 10 C-atoms, like e.g. poly(3-hexylthiophene).

Particularly preferred polymeric OSC compounds are polymers orcopolymers comprising one or more repeating units selected from thegroup consisting of thiophene-2,5-diyl, 3-substitutedthiophene-2,5-diyl, optionally substitutedthieno[2,3-b]thiophene-2,5-diyl, optionally substitutedthieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, 3-substitutedselenophene-2,5-diyl, optionally substituted indenofluorene, optionallysubstituted phenanthrene and optionally substituted triarylamine.

The composition according to the present invention can comprise between0.01 and 20% by weight, preferably between 0.1 and 15% by weight, morepreferably between 0.2 and 10% by weight and most preferably between0.25 and 5% by weight of OSC materials or the corresponding blend. Thepercent data relate to 100% of the solvent or solvent mixture. Thecomposition may comprise one or more than one, preferably 1, 2, 3 ormore than three OSC compounds.

The organic semiconductor compound used here is either a pure componentor a mixture of two or more components, at least one of which must havesemiconducting properties. In the case of the use of mixtures, however,it is not necessary for each component to have semiconductingproperties. Thus, for example, inert low-molecular-weight compounds canbe used together with semiconducting polymers. It is likewise possibleto use non-conducting polymers, which serve as inert matrix or binder,together with one or more low-molecular-weight compounds or furtherpolymers having semiconducting properties. For the purposes of thisapplication, the potentially admixed non-conducting component is takento mean an electro-optically inactive, inert, passive compound.

Preference is given to solutions of polymeric organic semiconductors,which optionally comprise further admixed substances. The molecularweight M_(w) of the polymeric organic semiconductor is preferablygreater than 10,000 g/mol, more preferably between 50,000 and 2,000,000g/mol and most preferably between 100,000 and 1,000,000 g/mol.

For the purposes of the present invention, polymeric organicsemiconductors are taken to mean, in particular, (i) substitutedpoly-p-arylenevinylenes (PAVs) as disclosed in EP 0443861, WO 94/20589,WO 98/27136, EP 1025183, WO 99/24526, DE 19953806 and EP 0964045 whichare soluble in organic solvents, (ii) substituted polyfluorenes (PFs) asdisclosed in EP 0842208, WO 00/22027, WO 00/22026, DE 19846767, WO00/46321, WO 99/54385 and WO 00155927 which are soluble in organicsolvents, (iii) substituted polyspirobifluorenes (PSFs) as disclosed inEP 0707020, WO 96/17036, WO 97/20877, WO 97/31048, WO 97/39045 and WO031020790 which are soluble in organic solvents, (iv) substitutedpoly-para-phenylenes (PPPs) or -biphenylenes as disclosed in WO92/18552, WO 95/07955, EP 0690086, EP 0699699 and WO 03/099901 which aresoluble in organic solvents, (v) substituted polydihydrophenanthrenes(PDHPs) as disclosed in WO 05/014689 which are soluble in organicsolvents, (vi) substituted poly-trans-indenofluorenes andpoly-cis-indenofluorenes (PIFs) as disclosed in WO 04/041901 and WO04/113412 which are soluble in organic solvents, (vii) substitutedpolyphenanthrenes as disclosed in DE 102004020298 which are soluble inorganic solvents, (viii) substituted polythiophenes (PTs) as disclosedin EP 1028136 and WO 95/05937 which are soluble in organic solvents,(ix) polypyridines (PPys) as disclosed in T. Yamamoto et at., J. Am.Chem. Soc. 1994, 116, 4832 which are soluble in organic solvents, (x)polypyrroles as disclosed in V. Gelling et at., Polym. Prepr. 2000, 41,1770 which are soluble in organic solvents, (xi) substituted, solublecopolymers having structural units from two or more of classes (i) to(x), as described, for example, in WO 02/077060, (xii) conjugatedpolymers as disclosed in Proc. of ICSM '98, Part I & II (in: Synth. Met1999, 101/102) which are soluble in organic solvents, (xiii) substitutedand unsubstituted polyvinylcarbazoles (PVKs), as disclosed, for example,in R. C. Penwell et al., J. Polym. Sci., Macromol Rev. 1978, 13, 63-160,(xiv) substituted and unsubstituted triarylamine polymers, as disclosed,for example, in JP 2000/072722, (xv) substituted and unsubstitutedpolysilylenes and polygermylenes, as disclosed, for example, in M. A.Abkowitz and M. Stolka, Synth. Met. 1996, 78, 333, and (xvi) solublepolymers containing phosphorescent units, as disclosed, for example inEP 1245659, WO 03/001616, WO 03/018653, WO 03/022908, WO 03/080687, EP1311138, WO 031102109, WO 04/003105, WO 04/015025, DE 102004032527 andsome of the specifications already cited above.

According to a further embodiment of the present invention, the organicsemiconducting compound preferably has a molecular weight of 5000 g/molor less, more preferably a molecular weight of 2000 g/mol or less.

According to a special embodiment of the present invention, the OSC canbe used for example as the active channel material in the semiconductingchannel of an OFET, or as a layer element of an organic rectifyingdiode.

In case of OFET devices, where the OFET layer contains an OSC as theactive channel material, it may be an n- or p-type OSC. Thesemiconducting channel may also be a composite of two or more OSCcompounds of the same type, i.e. either n- or p-type. Furthermore, ap-type channel OSC compound may for example be mixed with an n-type OSCcompound for the effect of doping the OSC layer. Multilayersemiconductors may also be used. For example, the OSC may be intrinsicnear the insulator interface and a highly doped region can additionallybe coated next to the intrinsic layer.

Preferred OSC compounds have a FET mobility of greater than 1×10⁻⁵cm²V⁻¹s⁻¹, more preferably greater than 1×10⁻² cm²V⁻¹s⁻¹.

Particularly preferred polymeric OSC compounds comprise repeating unitswhich are selected from formulae P1-P7:

wherein

-   n is an integer >1, preferably from 10 to 1,000,-   R on each occurrence identically or differently denotes H, F, Cl,    Br, I, CN, a straight-chain, branched or cyclic alkyl group having    from 1 to 40 C atoms, in which one or more C atoms are optionally    replaced by O, S, O—CO, CO—O, O—CO—O, CR⁰═CR⁰ or C≡C such that O-    and/or S-atoms are not linked directly to each other, and in which    one or more H atoms are optionally replaced by F, Cl, Br, I or CN,    or denotes an aryl or heteroaryl group having from 4 to 20 ring    atoms that is unsubstituted or substituted by one or more    non-aromatic groups R^(s), and wherein one or more groups R may also    form a mono- or polycyclic aliphatic or aromatic ring system with    one another and/or with the ring to which they are attached,-   R^(s) on each occurrence identically or differently denotes F, Cl,    Br, I, CN, Sn(R⁰⁰)₃, Si(R⁰⁰)₃ or)B(R⁰⁰)₂ a straight-chain, branched    or cyclic alkyl group having from 1 to 25 C atoms, in which one or    more C atoms are optionally replaced by O, S, O—CO, CO—O, O—CO—O,    CR⁰═CR⁰, C≡C such that O- and/or S-atoms are not linked directly to    each other, and in which one or more H atoms are optionally replaced    by F, Cl, Br, I or CN, or R^(s) denotes an aryl or heteroaryl group    having from 4 to 20 ring atoms that is unsubstituted or substituted    by one or more non-aromatic groups R^(s), and wherein one or more    groups R^(s) may also form a ring system with one another and/or    with R,-   R⁰ on each occurrence identically or differently denotes H, F, Cl,    CN, alkyl having from 1 to 12 C atoms or aryl or heteroaryl having    from 4 to 10 ring atoms,-   R⁰⁰ on each occurrence identically or differently denotes H or an    aliphatic or aromatic hydrocarbon group having from 1 to 20 C atoms,    wherein two groups R⁰⁰ may also form a ring together with the hetero    atom (Sn, Si or B) to which they are attached,-   r is 0, 1, 2, 3 or 4,-   s is 0, 1, 2, 3, 4 or 5,-   wherein R in formulae P1-P5 is preferably different from H.

Especially preferred monomeric OSC compounds are selected from the groupconsisting of substituted oligoacenes such as pentacene, tetracene oranthracene, or heterocyclic derivatives thereof, likebis(trialkylsilylethynyl)oligoacenes orbis(trialkylsilylethynyl)heteroacenes, as disclosed for example in U.S.Pat. No. 6,690,029, WO 2005/055248 A1 or U.S. Pat. No. 7,385,221.

Particularly preferred monomeric OSC compounds are selected from formulaM1 (polyacenes):

-   -   wherein each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and        R¹², which may be the same or different, independently        represents: hydrogen; an optionally substituted C₁-C₄₀ carbyl or        hydrocarbyl group; an optionally substituted C₁-C₄₀ alkoxy        group; an optionally substituted C₆-C₄₀ aryloxy group; an        optionally substituted C₇-C₄₀ alkylaryloxy group; an optionally        substituted C₂-C₄₀ alkoxycarbonyl group; an optionally        substituted C₇-C₄₀ aryloxycarbonyl group; a cyano group (—CN); a        carbamoyl group (—C(═O)NH₂); a haloformyl group (—C(═O)—X,        wherein X represents a halogen atom); a formyl group (—C(═O)—H);        an isocyano group; an isocyanate group; a thiocyanate group or a        thioisocyanate group; an optionally substituted amino group; a        hydroxy group; a nitro group; a CF₃ group; a halo group (Cl, Br,        F); or an optionally substituted silyl or alkynylsilyl group;        and    -   wherein independently each pair of R¹ and R², R² and R³, R³ and        R⁴, R⁷ and R⁸, R⁸ and R⁹, R⁹ and R¹⁰, is optionally        cross-bridged to form a C₄-C₄₀ saturated or unsaturated ring,        which saturated or unsaturated ring may be intervened by an        oxygen atom, a sulphur atom or a group of the formula        —N(R^(a))—, wherein R^(a) is a hydrogen atom or an optionally        substituted hydrocarbon group, or may optionally be substituted;        and    -   wherein one or more of the carbon atoms of the polyacene        skeleton may optionally be substituted by a heteroatom selected        from N, P, As, O, S, Se and Te; and    -   wherein independently any two or more of the substituents R¹-R¹²        which are located on adjacent ring positions of the polyacene        may, together, optionally constitute a further C₄-C₄₀ saturated        or unsaturated ring optionally intervened by O, S or —N(R^(a)),        where R^(a) is as defined above, or an aromatic ring system,        fused to the polyacene; and    -   wherein n is 0, 1, 2, 3 or 4 preferably n is 0, 1 or 2, most        preferably n is 0 or 2, meaning that the polyacene compound is a        pentacene compound (if n=2) or a “pseudo pentacene” compound (if        n=0).

Very preferred are compounds of formula M1a (substituted pentacenes):

-   -   wherein R¹, R², R³, R⁴, R⁷, R⁸, R⁹, R¹⁰, R¹⁵, R¹⁶, R¹⁷ each        independently are the same or different and each independently        represents: H; an optionally substituted C₁-C₄₀ carbyl or        hydrocarbyl group; an optionally substituted C₁-C₄₀ alkoxy        group; an optionally substituted C₆-C₄₀ aryloxy group; an        optionally substituted C₇-C₄₀ alkylaryloxy group; an optionally        substituted C₂-C₄₀ alkoxycarbonyl group; an optionally        substituted C₇-C₄₀ aryloxycarbonyl group; a cyano group (—CN); a        carbamoyl group (—C(═O)NH₂); a haloformyl group (—C(═O)—X,        wherein X represents a halogen atom); a formyl group (—C(═O)—H);        an isocyano group; an isocyanate group; a thiocyanate group or a        thioisocyanate group; an optionally substituted amino group; a        hydroxy group; a nitro group; a CF₃ group; a halo group (Cl, Br,        F); or an optionally substituted silyl group; and A represents        Silicon or Germanium; and    -   wherein independently each pair of R¹ and R², R² and R³, R³ and        R⁴, R⁷ and R⁸, R⁸ and R⁹, R⁹ and R¹⁰, R¹⁵ and R¹⁶, and R¹⁶ and        R¹⁷ is optionally cross-bridged with each other to form a C₄-C₄₀        saturated or unsaturated ring, which saturated or unsaturated        ring is optionally intervened by an oxygen atom, a sulphur atom        or a group of the formula —N(R^(a))—, wherein R^(a) is a        hydrogen atom or a hydrocarbon group, or is optionally        substituted; and    -   wherein one or more of the carbon atoms of the polyacene        skeleton is optionally substituted by a heteroatom selected from        N, P, As, O, S, Se and Te.

Further preferred are compounds of formula M1b (substitutedheteroacenes):

-   -   wherein R², R³, R⁸, R⁹, R¹⁵, R¹⁶, R¹⁷ each independently are the        same or different and each independently represents: H; an        optionally substituted C₁-C₄₀ carbyl or hydrocarbyl group; an        optionally substituted C₁-C₄₀ alkoxy group; an optionally        substituted C₆-C₄₀ aryloxy group; an optionally substituted        C₇-C₄₀ alkylaryloxy group; an optionally substituted C₂-C₄₀        alkoxycarbonyl group; an optionally substituted C₇-C₄₀        aryloxycarbonyl group; a cyano group (—CN); a carbamoyl group        (—C(═O)NH₂); a haloformyl group (—C(═O)—X, wherein X represents        a halogen atom); a formyl group (—C(═O)—H); an isocyano group;        an isocyanate group; a thiocyanate group or a thioisocyanate        group; an optionally substituted amino group; a hydroxy group; a        nitro group; a CF₃ group; a halo group (Cl, Br, F); or an        optionally substituted silyl group; and A represents Silicon or        Germanium; and    -   wherein independently each pair of R² and R³, R⁸ and R⁹, R¹⁵ and        R¹⁶, and R¹⁶ and R¹⁷ is optionally cross-bridged with each other        to form a C₄-C₄₀ saturated or unsaturated ring, which saturated        or unsaturated ring is optionally intervened by an oxygen atom,        a sulphur atom or a group of the formula —N(R^(a))—, wherein        R^(a) is a hydrogen atom or a hydrocarbon group, and is        optionally substituted; and    -   wherein one or more of the carbon atoms of the polyacene        skeleton is optionally substituted by a heteroatom selected from        N, P, As, O, S, Se and Te.

Especially preferred are compounds of subformula M1b, wherein at leastone pair of R² and R³, and R⁸ and R⁹ is cross-bridged with each other toform a C₄-C₄₀ saturated or unsaturated ring, which is intervened by anoxygen atom, a sulphur atom or a group of the formula —N(R^(a))—,wherein R^(a) is a hydrogen atom or a hydrocarbon group, and which isoptionally substituted.

Especially preferred are compounds of subformula M1b1 (silylethynylatedheteroacenes):

-   -   wherein    -   one of Y¹ and Y² denotes —CH═ or ═CH— and the other denotes —X—,    -   one of Y³ and Y⁴ denotes —CH═ or ═CH— and the other denotes —X—,

-   X is —O—, —S—, —Se— or —NR′″—,

-   R′ is H, F, Cl, Br, I, CN, straight-chain or branched alkyl or    alkoxy that have 1 to 20, preferably 1 to 8 C-atoms and are    optionally fluorinated or perfluorinated, optionally fluorinated or    perfluorinated aryl having 6 to 30 C-atoms, preferably C₆F₅, or    CO₂R″″, with R″″ being H, optionally fluorinated alkyl having 1 to    20 C-atoms or optionally fluorinated aryl having 2 to 30, preferably    5 to 20 C-atoms,

-   R″ is, in case of multiple occurrence independently of one another,    cyclic, straight-chain or branched alkyl or alkoxy that have 1 to    20, preferably 1 to 8 C-atoms, or aryl having 2 to 30 C-atoms, all    of which are optionally fluorinated or perfluorinated, with SiR″₃    preferably being trialkylsilyl,

-   R′″ is H or cyclic, straight-chain or branched alkyl with 1 to 10    C-atoms, preferably H,

-   m is 0 or 1,

-   o is 0 or 1.

Especially preferred are compounds of formula M1b1 wherein m and o are0, and/or X is S, and/or R′ is F.

In a preferred embodiment the compound of subformula M1b1 is providedand used as a mixture of the anti- and syn-isomers of the followingformulae

-   -   wherein X, R, R′, R″ m and o have independently of each other        one of the meanings given in formula M1b1 or one of the        preferred meanings given above and below, X is preferably S, and        m and o are preferably 0.

The term “carbyl group” as used above and below denotes any monovalentor multivalent organic radical moiety which comprises at least onecarbon atom either without any non-carbon atoms (like for example—C═C—), or optionally combined with at least one non-carbon atom such asN, O, S, P, Si, Se, As, Te or Ge (for example carbonyl etc.). The term“hydrocarbyl group” denotes a carbyl group that does additionallycontain one or more H atoms and optionally contains one or more heteroatoms like for example N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group comprising a chain of 3 or more C atomsmay also be straight-chain, branched and/or cyclic, including spiroand/or fused rings.

Preferred carbyl and hydrocarbyl groups include alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy,each of which is optionally substituted and has 1 to 40, preferably 1 to25, more preferably 1 to 18 C atoms, furthermore optionally substitutedaryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, furthermorealkylaryloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy andaryloxycarbonyloxy, each of which is optionally substituted and has 6 to40, preferably 7 to 40 C atoms, wherein all these groups optionallycontain one or more hetero atoms, especially selected from N, O, S, P,Si, Se, As, Te and Ge. The carbyl or hydrocarbyl group may be asaturated or unsaturated acyclic group, or a saturated or unsaturatedcyclic group. Unsaturated acyclic or cyclic groups are preferred,especially aryl, alkenyl and alkynyl groups (especially ethynyl). Wherethe C₁-C₄₀ carbyl or hydrocarbyl group is acyclic, the group may bestraight-chain or branched. The C₁-C₄₀ carbyl or hydrocarbyl groupincludes for example: a C₁-C₄₀ alkyl group, a C₂-C₄₀ alkenyl group, aC₂-C₄₀ alkynyl group, a C₃-C₄₀ alkyl group, a C₄-C₄₀ alkyldienyl group,a C₄-C₄₀ polyenyl group, a C₆-C₁₈ aryl group, a C₆-C₄₀ alkylaryl group,a C₆-C₄₀ arylalkyl group, a C₄-C₄₀ cycloalkyl group, a C₄-C₄₀cycloalkenyl group, and the like. Preferred among the foregoing groupsare a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynylgroup, a C₃-C₂₀ alkyl group, a C₄-C₂₀ alkyldienyl group, a C₆-C₁₂ arylgroup and a C₄-C₂₀ polyenyl group, respectively. Also included arecombinations of groups having carbon atoms and groups having heteroatoms, like e.g. an alkynyl group, preferably ethynyl, that issubstituted with a silyl group, preferably a trialkylsilyl group.

Aryl and heteroaryl preferably denote a mono-, bi- or tricyclic aromaticor heteroaromatic group with up to 25 C atoms that may also comprisecondensed rings and is optionally substituted with one or more groups L,wherein L is halogen or an alkyl, alkoxy, alkylcarbonyl oralkoxycarbonyl group with 1 to 12 C atoms, wherein one or more H atomsmay be replaced by F or Cl.

Especially preferred aryl and heteroaryl groups are phenyl in which, inaddition, one or more CH groups may be replaced by N, naphthalene,thiophene, selenophene, thienothiophene, dithienothiophene, fluorene andoxazole, all of which can be unsubstituted, mono- or polysubstitutedwith L as defined above.

Especially preferred substituents R, R^(s) and R¹⁻¹⁷ in the aboveformulae and subformulae are selected from straight chain, branched orcyclic alkyl having from 1 to 20 C atoms, which is unsubstituted ormono- or polysubstituted by F, Cl, Br or I, and wherein one or morenon-adjacent CH₂ groups are optionally replaced, in each caseindependently from one another, by —O—, —S—, —NR^(b)—, —SiR^(b)R^(c)—,—CX¹═CX²— or —C≡C— in such a manner that O and/or S atoms are not linkeddirectly to one another, or denotes optionally substituted aryl orheteroaryl preferably having from 1 to 30 C-atoms, with R^(b) and R^(c)being independently of each other H or alkyl having from 1 to 12C-atoms, and X¹ and X² being independently of each i other H, F, Cl orCN.

R¹⁵⁻¹⁷ and R″ are preferably identical or different groups selected froma C₁-C₄₀-alkyl group, preferably C₁-C₄-alkyl, most preferably methyl,ethyl, npropyl or isopropyl, a C₆-C₄₀-aryl group, preferably phenyl, aC₆-C₄₀-arylalkyl group, a C₁-C₄₀-alkoxy group, or a C₆-C₄₀-arylalkyloxygroup, wherein all these groups are optionally substituted for examplewith one or more halogen atoms. Preferably, R¹⁵⁻¹⁷ and R″ are eachindependently selected from optionally substituted C₁₋₁₂-alkyl, morepreferably C₁₋₄-alkyl, most preferably C₁₋₃-alkyl, for exampleisopropyl, and optionally substituted C₆₋₁₀-aryl, preferably phenyl.Further preferred is a silyl group of formula —SiR¹⁵R¹⁶ wherein R¹⁵ isas defined above and R¹⁶ forms a cyclic silyl alkyl group together withthe Si atom, preferably having 1 to 8 C atoms.

In one preferred embodiment all of R¹⁵⁻¹⁷, or all of R″, are identicalgroups, for example identical, optionally substituted, alkyl groups, asin triisopropylsilyl. Very preferably all of R¹⁵⁻¹⁷, or all of R″, areidentical, optionally substituted C₁₋₁₀, more preferably C₁₋₄, mostpreferably C₁₋₃ alkyl groups. A preferred alkyl group in this case isisopropyl.

Preferred groups —SiR¹⁵R¹⁶R¹⁷ and SiR″₃ include, without limitation,trimethylsilyl, triethylsilyl, tripropylsilyl, dimethylethylsilyl,diethylmethylsilyl, dimethylpropylsilyl, dimethylisopropylsilyl,dipropylmethylsilyl, diisopropylmethylsilyl, dipropylethylsilyl,diisopropylethylsilyl, diethylisopropylsilyl, triisopropylsilyl,trimethoxysilyl, triethoxysilyl, triphenylsilyl, diphenylisopropylsilyl,diisopropylphenylsilyl, diphenylethylsilyl, diethylphenylsilyl,diphenylmethylsilyl, triphenoxysilyl, dimethylmethoxysilyl,dimethylphenoxysilyl, methylmethoxyphenylsilyl, etc., wherein the alkyl,aryl or alkoxy group is optionally substituted.

According to a preferred embodiment of the present invention the OSCmaterial is an organic light emitting material and/or chargetransporting material. The organic light emitting materials and chargetransporting materials can be selected from standard materials known tothe skilled person and described in the literature. Organic lightemitting material according to the present application means a materialwhich emits light having a λ_(max) in the range from 400 to 700 nm.

Suitable phosphorescent compounds are, in particular, compounds whichemit light, preferably in the visible region, on suitable excitation andin addition contain at least one atom having an atomic number greaterthan 20, preferably greater than 38 and less than 84, more preferablygreater than 56 and less than 80. The phosphorescence emitters used arepreferably compounds which contain copper, molybdenum, tungsten,rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum,silver, gold or europium, in particular compounds which contain iridiumor platinum.

Particularly preferred organic phosphorescent compounds are compounds offormulae (1) to (4):

-   where-   DCy is, identically or differently on each occurrence, a cyclic    group which contains at least one donor atom, preferably nitrogen,    carbon in the form of a carbene or phosphorus, via which the cyclic    group is bonded to the metal, and which may in turn carry one or    more substituents R¹⁸; the groups DCy and CCy are connected to one    another via a covalent bond;-   CCy is, identically or differently on each occurrence, a cyclic    group which contains a carbon atom via which the cyclic group is    bonded to the metal and which may in turn carry one or more    substituents R¹⁸;-   A is, identically or differently on each occurrence, a monoanionic,    bidentate chelating ligand, preferably a diketonate ligand;-   R¹⁸ are identically or differently at each instance, and are F, Cl,    Br, I, NO₂, CN, a straight-chain, branched or cyclic alkyl or alkoxy    group having from 1 to 20 carbon atoms, in which one or more    nonadjacent CH₂ groups may be replaced by —O—, —S—, —NR¹⁹—,    —CONR¹⁹—, —CO—O—, —C═O—, —CH═CH— or —C≡C—, and in which one or more    hydrogen atoms may be replaced by F, or an aryl or heteroaryl group    which has from 4 to 14 carbon atoms and may be substituted by one or    more nonaromatic R¹⁸ radicals, and a plurality of substituents R¹⁸,    either on the same ring or on two different rings, may together in    turn form a mono- or polycyclic, aliphatic or aromatic ring system;    and-   R¹⁹ are identically or differently at each instance, and are a    straight-chain, branched or cyclic alkyl or alkoxy group having from    1 to 20 carbon atoms, in which one or more nonadjacent CH₂ groups    may be replaced by —O—, —S—, —CO—O—, —C═O—, —CH═CH— or —C≡C—, and in    which one or more hydrogen atoms may be replaced by F, or an aryl or    heteroaryl group which has from 4 to 14 carbon atoms and may be    substituted by one or more nonaromatic R¹⁸ radicals.

Formation of ring systems between a plurality of radicals R¹⁸ means thata bridge may also be present between the groups DCy and CCy.

Furthermore, formation of ring systems between a plurality of radicalsR¹⁸ means that a bridge may also be present between two or three ligandsCCy-DCy or between one or two ligands CCy-DCy and the ligand A, giving apolydentate or polypodal ligand system.

Examples of the emitters described above are revealed by theapplications WO 00/70655, WO 01/41512, WO 02/02714, WO 02/15645, EP1191613, EP 1191612, EP 1191614, WO 04/081017, WO 05/033244, WO05/042550, WO 05/113563, WO 06/008069, WO 06/061182, WO 06/081973 and DE102008027005. In general, all phosphorescent complexes as are used inaccordance with the prior art for phosphorescent OLEDs and as are knownto the person skilled in the art in the area of organicelectroluminescence are suitable, and the person skilled in the art willbe able to use further phosphorescent compounds without inventive step.In particular, it is known to the person skilled in the art whichphosphorescent complexes emit with which emission colour.

Examples of preferred phosphorescent compounds are shown in thefollowing table.

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

(18)

(19)

(20)

(21)

(22)

(23)

(24)

(25)

(26)

(27)

(28)

(29)

(30)

(31)

(32)

(33)

(34)

(35)

(36)

(37)

(38)

(39)

(40)

(41)

(42)

(43)

(44)

(45)

(46)

(47)

(48)

(49)

(50)

(51)

(52)

(53)

(54)

(55)

(56)

(57)

(58)

(59)

(60)

(61)

(62)

(63)

(64)

(65)

(66)

(67)

(68)

(69)

(70)

(71)

(72)

(73)

(74)

(75)

(76)

(77)

(78)

(79)

(80)

(81)

(82)

(83)

(84)

(85)

(86)

(87)

(88)

(89)

(90)

(91)

(92)

(93)

(94)

(95)

(96)

(97)

(98)

(99)

(100)

(101)

(102)

(103)

(104)

(105)

(106)

(107)

(108)

(109)

(110)

(111)

(112)

(113)

(114)

(115)

(116)

(117)

(118)

(119)

(120)

(121)

(122)

(123)

(124)

(125)

(126)

(127)

(128)

(129)

(130)

(131)

(132)

(133)

(134)

(135)

(136)

(137)

(138)

(139)

(140)

Preferred dopants are selected from the class of the monostyrylamines,the distyrylamines, the tristyrylamines, the tetrastyrylamines, thestyrylphosphines, the styryl ethers and the arylamines. Amonostyrylamine is taken to mean a compound which contains onesubstituted or unsubstituted styryl group and at least one, preferablyaromatic, amine. A distyrylamine is taken to mean a compound whichcontains two substituted or un-substituted styryl groups and at leastone, preferably aromatic, amine. A tristyrylamine is taken to mean acompound which contains three substituted or unsubstituted styryl groupsand at least one, preferably aromatic, amine. A tetrastyrylamine istaken to mean a compound which contains four substituted orunsubstituted styryl groups and at least one, preferably aromatic,amine. The styryl groups are particularly preferably stilbenes, whichmay also be further substituted. Corresponding phosphines and ethers aredefined analogously to the amines. For the purposes of the presentinvention, an arylamine or an aromatic amine is taken to mean a compoundwhich contains three substituted or unsubstituted aromatic orheteroaromatic ring systems bonded directly to the nitrogen. At leastone of these aromatic or heteroaromatic ring systems is preferably acondensed ring system, particularly preferably having at least 14aromatic ring atoms. Preferred examples thereof are aromaticanthraceneamines, aromatic anthracenediamines, aromatic pyreneamines,aromatic pyrenediamines, aromatic chryseneamines or aromaticchrysenediamines. An aromatic anthraceneamine is taken to mean acompound in which one diarylamino group is bonded directly to ananthracene group, preferably in the 9-position. An aromaticanthracenediamine is taken to mean a compound in which two diarylaminogroups are bonded directly to an anthracene group, preferably in the9,10-position. Aromatic pyreneamines, pyrenediamines, chryseneamines andchrysenediamines are defined analogously thereto, where the diarylaminogroups are preferably bonded to the pyrene in the 1-position or in the1,6-position. Further preferred dopants are selected fromindenofluoreneamines or indenofluorenediamines, for example inaccordance with WO 06/122630, benzoindenofluoreneamines orbenzoindenofluorenediamines, for example in accordance with WO08/006,449, and dibenzoindenofluoreneamines ordibenzoindenofluorenediamines, for example in accordance with WO07/140,847. Examples of dopants from the class of the styrylamines aresubstituted or unsubstituted tristilbeneamines or the dopants describedin WO 06/000388, WO 06/058737, WO 06/000389, WO 07/065,549 and WO07/115,610. Preference is furthermore given to the condensedhydrocarbons disclosed in DE 102008035413.

Suitable dopants are furthermore the structures depicted in thefollowing table, and the derivatives of these structures disclosed in JP06/001973, WO 04/047499, WO 06/098080, WO 07/065,678, US 2005/0260442and WO 04/092111.

(141)

(142)

(143)

(144)

(145)

(146)

The proportion of the dopant in the mixture of the emitting layer isbetween 0.1 and 50.0% by weight, preferably between 0.5 and 20.0% byweight, more preferably between 1.0 and 10.0% by weight.Correspondingly, the proportion of the host material is between 50.0 and99.9% by weight, preferably between 80.0 and 99.5% by weight, morepreferably between 90.0 and 99.0% by weight.

Suitable host materials for this purpose are materials from variousclasses of substance. Preferred host materials are selected from theclasses of the oligoarylenes (for example 2,2′,7,7′-tetraphenylspirobifluorene in accordance with EP 676461 ordinaphthylanthracene), in particular the oligoarylenes containingcondensed aromatic groups, the oligoarylenevinylenes (for example DPVBior spiro-DPVBi in accordance with EP 676461), the polypodal metalcomplexes (for example in accordance with WO 04/081017), thehole-conducting compounds (for example in accordance with WO 04/058911),the electron-conducting compounds, in particular ketones, phosphineoxides, sulfoxides, etc. (for example in accordance with WO 05/084081and WO 05/084082), the atropisomers (for example in accordance with WO06/048268), the boronic acid derivatives (for example in accordance withWO 06/117052) or the benzanthracenes (for example in accordance with WO08/145,239). Suitable host materials are furthermore also thebenzo[c]phenanthrene compounds according to the invention which aredescribed above. Apart from the compounds according to the invention,particularly preferred host materials are selected from the classes ofthe oligoarylenes containing naphthalene, anthracene, benzanthraceneand/or pyrene or atropisomers of these compounds, theoligoarylenevinylenes, the ketones, the phosphine oxides and thesulfoxides. Apart from the benzo[c]phenanthrene compounds according tothe invention, very particularly preferred host materials are selectedfrom the classes of the oligoarylenes containing anthracene,benzanthracene and/or pyrene or atropisomers of these compounds. For thepurposes of this invention, an oligoarylene is intended to be taken tomean a compound in which at least three aryl or arylene groups arebonded to one another.

Suitable host materials are furthermore, for example, the materialsdepicted in the following table, and derivatives of these materials, asdisclosed in WO 04/018587, WO 08/006,449, U.S. Pat. No. 5,935,721, US2005/0181232, JP 2000/273056, EP 681019, US 2004/0247937 and US2005/0211958.

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For the purposes of this invention, a hole-injection layer is a layerwhich is directly adjacent to the anode. For the purposes of thisinvention, a hole-transport layer is a layer which is located between ahole-injection layer and an emission layer. It may be preferred for themto be doped with electron-acceptor compounds, for example with F₄-TCNQor with compounds as described in EP 1476881 or EP 1596445.

Apart from the materials according to the invention, suitablechargetransport materials, as can be used in the hole-injection orhole-transport layer or in the electron-injection or electron-transportlayer of the organic electroluminescent device according to theinvention, are, for example, the compounds disclosed in Y. Shirota etal., Chem. Rev. 2007, 107(4), 953-1010, or other materials as employedin these layers in accordance with the prior art.

Examples of preferred hole-transport materials which can be used in ahole-transport or hole-injection layer of the electroluminescent deviceaccording to the invention are indenofluoreneamines and derivatives (forexample in accordance with WO 06/122630 or WO 06/100896), the aminederivatives as disclosed in EP 1661888, hexaazatriphenylene derivatives(for example in accordance with WO 01/049806), amine derivatives withcondensed aromatics (for example in accordance with U.S. Pat. No.5,061,569), the amine derivatives as disclosed in WO 95/09147,monobenzoindenofluoreneamines (for example in accordance with WO08/006,449) or dibenzoindenofluoreneamines (for example in accordancewith WO 07/140,847). Suitable hole-transport and hole-injectionmaterials are furthermore derivatives of the compounds depicted above,as disclosed in JP 2001/226331, EP 676461, EP 650955, WO 01/049806, U.S.Pat. No. 4,780,536, WO 98/30071, EP 891121, EP 1661888, JP 2006/253445,EP 650955, WO 06/073054 and U.S. Pat. No. 5,061,569.

Suitable hole-transport or hole-injection materials are furthermore, forexample, the materials indicated in the following table.

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Suitable electron-transport or electron-injection materials which can beused in the electroluminescent device according to the invention are,for example, the materials indicated in the following table. Suitableelectron-transport and electron-injection materials are furthermorederivatives of the compounds depicted above, as disclosed in JP2000/053957, WO 03/060956, WO 04/028217 and WO 04/080975.

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Suitable matrix materials for the compounds according to the inventionare ketones, phosphine oxides, sulfoxides and sulfones, for example inaccordance with WO 04/013080, WO 04/093207, WO 06/005627 or DE102008033943, triarylamines, carbazole derivatives, for example CBP(N,N-biscarbazolyl-biphenyl) or the carbazole derivatives disclosed inWO 05/039246, US 2005/0069729, JP 2004/288381, EP 1205527 or WO08/086,851, indolocarbazole derivatives, for example in accordance withWO 07/063,754 or WO 08/056,746, azacarbazoles, for example in accordancewith EP 1617710, EP 1617711, EP 1731584 or JP 2005/347160, bipolarmatrix materials, for example in accordance with WO 07/137,725, silanes,for example in accordance with WO 05/111172, azaboroles or boronicesters, for example in accordance with WO 06/117052, triazinederivatives, for example in accordance with DE 102008036982, WO07/063,754 or WO 08/056,746, or zinc complexes, for example inaccordance with DE 102007053771.

Preference is furthermore also given to solutions of non-conducting,electronically inert polymers (matrix polymers; inert polymeric binders)which comprise admixed low-molecular-weight, oligomeric, dendritic,linear or branched and/or polymeric organic and/or organometallicsemiconductors. Preferably, the composition may comprise 0.5 to 10% byweight inert polymeric binders.

Optionally, the OSC composition comprises one or more organic binders,preferably polymeric binders to adjust the rheological properties, asdescribed for example in WO 2005/055248 A1, in particular an organicbinder which has a low permittivity (∈) at 1,000 Hz of 3.3 or less, verypreferably in a proportion of binder to OSC compounds from 20:1 to 1:20,preferably 10:1 to 1:10, more preferably 5:1 to 1:5, most preferably 1:2to 1:5 by weight.

The binder is selected for example from poly(α-methylstyrene),polyvinylcinnamate, poly(4-vinylbiphenyl) or poly(4-methylstyrene), orblends thereof. The binder may also be a semiconducting binder selectedfor example from poly-arylamines, polyfluorenes, polythiophenes,polyspirobifluorenes, substituted polyvinylenephenylenes, polycarbazolesor polystilbenes, or copolymers thereof.

According to a preferred embodiment of the present invention, an inertbinder is a polymer having a glass transition temperature in the rangeof −70 to 160° C., preferably 0 to 150° C., more preferably 50 to 140°C. and most preferably 70 to 130° C. The glass transition temperaturecan be determined by measuring the DSC of the polymer (DIN EN ISO 11357,heating rate 10° C. per minute).

The composition according to the present invention may additionallycomprise one or more further components like for example surface-activecompounds, lubricating agents, conductive additives, dispersing agents,hydrophobing agents, adhesive agents, flow improvers, defoaming agents,deaerators, diluents which may be reactive or non-reactive, auxiliaries,colourants, dyes or pigments, sensitizers, stabilizers, nanoparticles orinhibitors. However, these further components should not be oxidising orotherwise capable of chemically reacting with the OSC or have anelectrically doping effect on the OSC.

Surprising improvements can be achieved with volatile wetting agents.The term “volatile” as used above and below means that the agent can beremoved from the organic semiconducting materials by evaporation, afterthese materials have been deposited onto a substrate of an OE device,under conditions (like temperature and/or reduced pressure) that do notsignificantly damage these materials or the OE device. Preferably thismeans that the wetting agent has a boiling point or sublimationtemperature of <350° C., more preferably ≦300° C., most preferably ≦250°C., at the pressure employed, very preferably at atmospheric pressure(1013 hPa). Evaporation can also be accelerated e.g. by applying heatand/or reduced pressure. Preferably, the wetting agents are not capableof chemically reacting with the OSC compounds. In particular they areselected from compounds that do not have a permanent doping effect onthe OSC material (e.g. by oxidising or otherwise chemically reactingwith the OSC material). Therefore, the formulation preferably should notcontain additives, like e.g. oxidants or protonic or lewis acids, whichreact with the OSC materials by forming ionic products.

Surprising effects can be accomplished by compositions comprisingvolatile components having similar boiling points. Preferably, thedifference of the boiling point of the wetting agent and the organicsolvent is in the range of −50° C. to 50° C., more preferably in therange of −30° C. to 30° C. and most preferably in the range of −20° C.to 20° C.

Preferred wetting agents are non-aromatic compounds. With furtherpreference the wetting agents are non-ionic compounds. Particular usefulwetting agents comprise a surface tension of at most 35 mN/m, preferablyof at most 30 mN/m, and more preferably of at most 25 mN/m. The surfacetension can be measured using a FTA (First Ten Angstrom) 125 contactangle goniometer at 25° C. Details of the method are available fromFirst Ten Angstrom as published by Roger P. Woodward, Ph.D. “SurfaceTension Measurements Using the Drop Shape Method”. Preferably, thependant drop method can be used to determine the surface tension.

According to a special aspect of the present invention, the differenceof the surface tension of the organic solvent and the wetting agent ispreferably at least 1 mN/m, preferably at least 5 mN/m and morepreferably at least 10 mN/m.

Unexpected improvements can be achieved by wetting agents comprising amolecular weight of at least 100 g/mol, preferably at least 150 g/mol,more preferably at least 180 g/mol and most preferably at least 200g/mol.

Suitable and preferred wetting agents that do not oxidise or otherwisechemically react with the OSC materials are selected from the groupconsisting of siloxanes, alkanes, amines, alkenes, alkynes, alcoholsand/or halogenated derivates of these compounds. Furthermore,fluoroethers, fluoroesters and/or fluoroketones can be used. Morepreferably, these compounds are selected from methylsiloxanes having 6to 20 carbon atoms, especially 8 to 16 carbon atoms; C₇-C₁₄ alkanes,C₇-C₁₄ alkenes, C₇-C₁₄ alkynes, alcohols having 7 to 14 carbon atoms,fluoroethers having 7 to 14 carbon atoms, fluoroesters having 7 to 14carbon atoms and fluoroketones having 7 to 14 carbon atoms. Mostpreferred wetting agents are methylsiloxanes having 8 to 14 carbonatoms.

Useful and preferred alkanes having 7 to 14 carbon atoms includeheptane, octane, nonane, decane, undecane, dodecane, tridecane,tetradecane, 3-methylheptane, 4-ethylheptane, 5-propyldecane,trimethylcyclohexane and decalin.

Halogenated alkanes having 7 to 14 carbon atoms include 1-chloroheptane,1,2-dichlorooctane, tetrafluorooctane, decafluorododecane,perfluorononane, 1,1,1-trifluoromethyldecane, andperfluoromethyldecalin.

Useful and preferred alkenes having 7 to 14 carbon atoms includeheptene, octene, nonene, 1-decene, 4-decene, undecene, dodecene,tridecene, tetradecene, 3-methylheptene, 4-ethylheptene, 5-propyldecene,and trimethylcyclohexene.

Halogenated alkenes having 7 to 14 carbon atoms include1,2-dichlorooctene, tetrafluorooctene, decafluorododecene,perfluorononene, and 1,1,1-trifluoromethyldecene.

Useful and preferred alkynes having 7 to 14 carbon atoms include octyne,nonyne, 1-decyne, 4-decyne, dodecyne, tetradecyne, 3-methylheptyne,4-ethylheptyne, 5-propyldecyne, and trimethylcyclohexyne.

Halogenated alkynes having 7 to 14 carbon atoms include1,2-dichlorooctyne, tetrafluorooctyne, decafluorododecyne,perfluorononyne, and 1,1,1-trifluoromethyldecyne.

Useful and preferred alcanols having 7 to 14 carbon atoms include,heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol,tetradecanol, 3-methylheptanol, 3,5-dimethyl-1-hexyn-3-ol,4-ethylheptanol, 5-propyldecanol, trimethylcyclohexanol andhydroxyldecalin.

Halogenated alkanols having 7 to 14 carbon atoms include1-chloroheptanol, 1,2-dichlorooctanol, tetrafluorooctanol,decafluorododecanol, perfluorononanol, 1,1,1-trifluoromethyldecanol, and2-trifluoromethyl-1-hydroxydecalin.

Useful and preferred fluoroethers having 7 to 14 carbon atoms include3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6 dodecafluoro-2-trifluoromethylhexane,3-propoxy-1,1,1,2,3,4,4,5,5,6,6,6 dodecafluoro-2-trifluoromethylhexane,and 3-propoxy-1,1,1,2,3,4,4,5,5,5 decafluoro-2-trifluoromethylpentane.

Useful and preferred fluoroesters having 7 to 14 carbon atoms include3-(1,1,1,2,3,4,4,5,5,6,6,6dodecafluoro-2-trifluoromethylhexyl)ethanoate, and3-(1,1,1,2,3,4,4,5,5,5 decafluoro-2-trifluoromethylpentyl)propanoate.

Useful and preferred fluoroketones having 7 to 14 carbon atoms include3-(1,1,1,2,3,4,4,5,5,6,6,6dodecafluoro-2-trifluoromethylhexyl)ethylketone, and3-(1,1,1,2,3,4,4,5,5,5 decafluoro-2-trifluoromethylpentyl)propylketone.

Useful and preferred siloxanes include hexamethyldisiloxane,octamethyltrisiloxane, decamethyltetrasiloxane,dodecamethylpentasiloxane, and tetradecamethylhexasiloxane.

Preferably, the composition may comprise at most 5% by weight of wettingadditives. More preferably, the composition comprises 0.01 to 3% byweight, most preferably 0.1 to 1% by weight of wetting agent.

The composition according to the present invention can be used for thepreparation of organic electronic (OE) devices, for example transistorslike OFETs or organic photovoltaic (OPV) devices like diodes or solarcells.

Especially preferred OE devices are OFETs. A preferred OFET according tothe present invention comprises the following components:

-   -   optionally a substrate (1),    -   a gate electrode (2),    -   an insulator layer comprising a dielectric material (3),    -   an OSC layer (4)    -   source and drain electrodes (5),    -   optionally one or more protection or passivation layers (6).

FIG. 1A exemplarily and schematically depicts a typical bottom gate(BG), top contact (TC) OFET device according to the present invention,comprising a substrate (1), a gate electrode (2), a layer of dielectricmaterial (3) (also known as gate insulator layer), an OSC layer (4), andsource and drain (S/D) electrodes (5), and an optional passivation orprotection layer (6).

The device of FIG. 1A can be prepared by a process comprising the stepsof depositing a gate electrode (2) on a substrate (1), depositing adielectric layer (3) on top of the gate electrode (2) and the substrate(1), depositing an OSC layer (4) on top of the dielectric layer (3),depositing S/D electrodes (5) on top of the OSC layer (4), andoptionally depositing a passivation or protection layer (6) on top ofthe S/D electrodes (5) and the OSC layer (4).

FIG. 1B exemplarily and schematically depicts a typical bottom gate(BG), bottom contact (BC) OFET device according to the presentinvention, comprising a substrate (1), a gate electrode (2), adielectric layer (3), S/D electrodes (5), an OSC layer (4), and anoptional passivation or protection layer (6).

The device of FIG. 1B can be prepared by a process comprising the stepsof depositing a gate electrode (2) on a substrate (1), depositing adielectric layer (3) on top of the gate electrode (2) and the substrate(1), depositing S/D electrodes (5) on top of the dielectric layer (3),depositing an OSC layer (4) on top of the S/D electrodes (4) and thedielectric layer (3), and optionally depositing a passivation orprotection layer (6) on top of the OSC layer (4).

FIG. 2 exemplarily and schematically depicts a top gate (TG) OFET deviceaccording to the present invention, comprising a substrate (1), sourceand drain electrodes (5), an OSC layer (4), a dielectric layer (3), anda gate electrode (2), and an optional passivation or protection layer(6).

The device of FIG. 2 can be prepared by a process comprising the stepsof depositing S/D electrodes (5) on a substrate (1), depositing an OSClayer (4) on top of the S/D electrodes (4) and the substrate (1),depositing a dielectric layer (3) on top of the OSC layer (4),depositing a gate electrode (2) on top of the dielectric layer (3), andoptionally depositing a passivation or protection layer (6) on top ofthe gate electrode (2) and the dielectric layer (3).

The passivation or protection layer (6) in the devices described inFIGS. 1A, 1B and 2 has the purpose of protecting the OSC layer and theS/D or gate electrodes from further layers or devices that may be laterprovided thereon, and/or from environmental influence.

The distance between the source and drain electrodes (5), as indicatedby the double arrow in FIGS. 1A, 1B and 2, is the channel area.

In case of formulations for use in OPV cells, the formulation preferablycomprises or contains, more preferably consists essentially of, mostpreferably consists exclusively of, a p-type semiconductor and a n-typesemiconductor, or an acceptor and a donor material. A preferred materialof this type is a blend or mixture of poly(3-substituted thiophene) orP3AT with a C₆₀ or C₇₀ fullerene or modified C₆₀ molecule like PCBM[(6,6)phenyl C61-butyric acid methyl ester], as disclosed for example inWO 94/05045 A1, wherein preferably the ratio of P3AT to fullerene isfrom 2:1 to 1:2 by weight, more preferably from 1.2:1 to 1:1.2 byweight.

FIG. 3 and FIG. 4 exemplarily and schematically depict typical andpreferred OPV devices according to the present invention [see alsoWaldauf et al., Appl. Phys. Lett. 89, 233517 (2006)].

An OPV device as shown in FIG. 3 preferably comprises:

-   -   a low work function electrode (31) (for example a metal, such as        aluminum), and a high work function electrode (32) (for example        ITO), one of which is transparent,    -   a layer (33) (also referred to as “active layer”) comprising a        hole transporting material and an electron transporting        material, preferably selected from OSC materials, situated        between the electrodes (31,32); the active layer can exist for        example as a bilayer or two distinct layers or blend or mixture        of p and n type semiconductor,    -   an optional conducting polymer layer (34), for example        comprising a blend of PEDOT:PSS        (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)),        situated between the active layer (33) and the high work        function electrode (32), to modify the work function of the high        work function electrode to provide an ohmic contact for holes,    -   an optional coating (35) (for example of LiF) on the side of the        low workfunction electrode (31) facing the active layer (33), to        provide an ohmic contact for electrons.

An inverted OPV device as shown in FIG. 4 preferably comprises:

-   -   a low work function electrode (41) (for example a metal, such as        gold), and a high work function electrode (42) (for example        ITO), one of which is transparent,    -   a layer (43) (also referred to as “active layer”) comprising a        hole transporting material and an electron transporting        material, preferably selected from OSC materials, situated        between the electrodes (41,42); the active layer can exist for        example as a bilayer or two distinct layers or blend or mixture        of p and n type semiconductor,    -   an optional conducting polymer layer (44), for example        comprising a blend of PEDOT:PSS, situated between the active        layer (43) and the low work function electrode (41) to provide        an ohmic contact for electrons,    -   an optional coating (45) (for example of TiO_(x)) on the side of        the high workfunction electrode (42) facing the active layer        (43), to provide an ohmic contact for holes.

The hole transporting polymer is for example a polythiophene. Theelectron transporting material is for example an inorganic material suchas zinc oxide or cadmium selenide, or an organic material such as afullerene derivate (like for example PCBM) or a polymer (see for exampleCoakley, K. M. and McGehee, M. D. Chem. Mater. 2004, 16, 4533). If thebilayer is a blend an optional annealing step may be necessary tooptimize device performance.

During the process of preparing an OE device, the OSC layer is depositedonto a substrate, followed by removal of the solvent together with anyvolatile additive(s) present, to form a film or layer.

Various substrates may be used for the fabrication of OE devices, forexample glass, ITO coated glass, ITO glass with pre coated layersincluding PEDOT, PANI etc, or plastics, plastics materials beingpreferred, examples including alkydresins, allylesters,benzocyclobutenes, butadienestyrene, cellulose, celluloseacetate,epoxide, epoxy polymers, ethylenechlorotrifluoroethylene,ethylene-tetra-fluoroethylene, fibre glass enhanced plastic,fluorocarbon polymers, hexafluoropropylenevinylidene-fluoride copolymer,high density polyethylene, parylene, polyamide, polyimide, polyaramid,polydimethylsiloxane, polyethersulphone, polyethylene,polyethylenenaphthalate, polyethyleneterephthalate, polyketone,polymethylmethacrylate, polypropylene, polystyrene, polysulphone,polytetrafluoroethylene, polyurethanes, polyvinylchloride, siliconerubbers, silicones, and flexible films with ITO, or other conductinglayers and barrier layers e.g. Vitex film.

Preferred substrate materials are polyethyleneterephthalate, polyimide,and polyethylenenaphthalate. The substrate may be any plastic material,metal or glass coated with the above materials. The substrate shouldpreferably be homogeneous to ensure good pattern definition. Thesubstrate may also be uniformly pre-aligned by extruding, stretching,rubbing or by photochemical techniques to induce the orientation of theorganic semiconductor in order to enhance carrier mobility.

The electrodes can be deposited by liquid coating, such as spray-, dip-,web- or spin-coating, or by vacuum deposition or vapor depositionmethods. Suitable electrode materials and deposition methods are knownto the person skilled in the art. Suitable electrode materials include,without limitation, inorganic or organic materials, or composites of thetwo. Examples for suitable conductor or electrode materials includepolyaniline, polypyrrole, PEDOT or doped conjugated polymers, furtherdispersions or pastes of graphite or particles of metal such as Au, Ag,Cu, Al, Ni or their mixtures as well as sputter coated or evaporatedmetals such as Cu, Cr, Pt/Pd or metal oxides such as indium tin oxide(ITO). Organometallic precursors may also be used deposited from aliquid phase.

Deposition of the OSC layer can be achieved by standard methods that areknown to the skilled person and are described in the literature.Suitable and preferred deposition methods include liquid coating andprinting techniques. Very preferred deposition methods include, withoutlimitation, dip coating, spin coating, spray coating, aerosol jetting,ink jet printing, nozzle printing, letter-press printing, screenprinting, gravure printing, doctor blade coating, roller printing,reverse-roller printing, offset lithography printing, flexographicprinting, web printing, spray coating, dip coating, curtain coating,brush coating, slot dye coating or pad printing. Gravure, flexographicand inkjet printing are more preferred. Inkjet printing is mostpreferred.

According to a special aspect, an insulator layer can be deposited on asubstrate in order to achieve a special type of an OE according to thepresent invention. Preferably, the insulator layer is deposited bysolution processing, very preferably using a solution of a dielectricmaterial, which is optionally cross-linkable, in one or more organicsolvents. Preferably the solvent used for depositing the dielectricmaterial is orthogonal to the solvent used for depositing the OSCmaterial, and vice versa.

When spin coating is used as deposition method, the OSC or dielectricmaterial is spun for example between 1000 and 2000 rpm for a period offor example 30 seconds to give a layer with a typical layer thicknessbetween 0.5 and 1.5 μm. After spin coating the film can be heated at anelevated temperature to remove all residual volatile solvents.

If a cross-linkable dielectric is used, it is preferably cross-linkedafter deposition by exposure to electron beam or electromagnetic(actinic) radiation, like for example X-ray, UV or visible radiation.For example, actinic radiation can be used having a wavelength of from50 nm to 700 nm, preferably from 200 to 450 nm, more preferably from 300to 400 nm. Suitable radiation dosages are typically in the range from 25to 3,000 mJ/cm². Suitable radiation sources include mercury,mercury/xenon, mercury/halogen and xenon lamps, argon or xenon lasersources, x-ray, or e-beam. The exposure to actinic radiation will inducea cross-linking reaction in the cross-linkable groups of the dielectricmaterial in the exposed regions. It is also possible for example to usea light source having a wavelength outside the absorption band of thecross-linkable groups, and to add a radiation sensitive photosensitizerto the cross-linkable material.

Optionally the dielectric material layer is annealed after exposure toradiation, for example at a temperature from 70° C. to 130° C., forexample for a period of from 1 to 30 minutes, preferably from 1 to 10minutes. The annealing step at elevated temperature can be used tocomplete the cross-linking reaction that was induced by the exposure ofthe cross-linkable groups of the dielectric material to photoradiation.

After application of the inventive composition onto a substrate, aleveling step can be preferably performed. Surprising improvements canbe achieved by heating and/or annealing the obtained layer comprisingthe solvent. Preferably, the heating and/or annealing is performed for aperiod of time in the range of 1 to 300 seconds, more preferably in therange of 2 to 100 seconds The temperature of the leveling step dependson the melting point of the solvent. Preferably, the temperature of theleveling step is situated in the range of 1° C. to 20° C., morepreferably of 2° C. to 5° C. above the melting point of the solvent.

Removal of the solvent and any volatile additive(s) is preferablyachieved by evaporation, for example by exposing the deposited layer tohigh temperature and/or reduced pressure, preferably at −50° C. to 200°C., more preferably 20° C. to 135° C. According to a special aspect ofthe present invention, the solvent(s) and any volatile additive can beevaporated under reduced pressure. Preferably, the pressure for solventevaporation ranges from 10⁻³ mbar to 1 bar, more preferably from 10⁻²mbar to 100 mbar and most preferably from 0.1 mbar to 10 mbar. Moreover,the evaporation of the solvent can be preferably achieved below themelting point of the solvent. Astonishing improvements can be obtainedby a evaporation temperature preferably ranging from 0.1° C. to 40° C.,more preferably from 1° C. to 30° C. below the melting point of thesolvent.

The present composition provides an improved method for achievingmultilayer OE devices. Astonishing improvements can be achieved bymethods wherein at least two layers comprising organic semiconductingcompounds are applied and the second layer is achieved by using acomposition of the present invention.

The thickness of the OSC layer is preferably from 1 nm to 50 μm, morepreferably from 2 to 1000 nm and most preferably 3 to 500 nm. Preferredlayers comprising organic light emitting materials and/or chargetransporting materials can have a thickness in the range of 2 to 150 nm.

Further to the materials and methods as described above and below, theOE device and its components can be prepared from standard materials andstandard methods, which are known to the person skilled in the art anddescribed in the literature.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Each feature disclosed in this specification, unless statedotherwise, may be replaced by alternative features serving the same,equivalent or similar purpose. Thus, unless stated otherwise, eachfeature disclosed is one example only of a generic series of equivalentor similar features.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

It will be appreciated that many of the features described above,particularly of the preferred embodiments, are inventive in their ownright and not just as part of an embodiment of the present invention.Independent protection may be sought for these features in addition toor alternative to any invention presently claimed.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components.

The term “polymer” includes homopolymers and copolymers, e.g.statistical, alternating or block copolymers. In addition, the term“polymer” as used hereinafter does also include oligomers anddendrimers. Dendrimers are typically branched macromolecular compoundsconsisting of a multifunctional core group onto which further branchedmonomers are added in a regular way giving a tree-like structure, asdescribed e.g. in M. Fischer and F. Vögtle, Angew. Chem., Int. Ed. 1999,38, 885.

The term “conjugated polymer” means a polymer containing in its backbone(or main chain) mainly C atoms with sp²-hybridisation, or optionallysp-hybridisation, which may also be replaced by hetero atoms, enablinginteraction of one π-orbital with another across an intervening σ-bond.In the simplest case this is for example a backbone with alternatingcarbon-carbon (or carbon-hetero atom) single and multiple (e.g. doubleor triple) bonds, but does also include polymers with units like1,3-phenylene. “Mainly” means in this connection that a polymer withnaturally (spontaneously) occurring defects, which may lead tointerruption of the conjugation, is still regarded as a conjugatedpolymer. Also included in this meaning are polymers wherein the backbonecomprises for example units like arylamines, arylphosphines and/orcertain heterocycles (i.e. conjugation via N-, O-, P- or S-atoms) and/ormetal organic complexes (i.e. conjugation via a metal atom). The term“conjugated linking group” means a group connecting two rings (usuallyaromatic rings) consisting of C atoms or hetero atoms withsp²-hybridisation or sp-hybridisation. See also “IUPAC Compendium ofChemical terminology, Electronic version”.

Unless stated otherwise, the molecular weight is given as the numberaverage molecular weight M_(n) or as weight average molecular weightM_(w), which unless stated otherwise are determined by gel permeationchromatography (GPC) against polystyrene standards.

The degree of polymerization (n) means the number average degree ofpolymerization, unless stated otherwise given as n=M_(n)/M_(U), whereinM_(U) is the molecular weight of the single repeating unit.

The term “small molecule” means a monomeric, i.e. a non-polymericcompound.

Unless stated otherwise, percentages of solids are percent by weight(“wt. %”), percentages or ratios of liquids (like e.g. in solventmixtures) are percent by volume (“vol. %”), and all temperatures aregiven in degrees Celsius (° C.).

Unless stated otherwise, concentrations or proportions of mixturecomponents, given in percentages or ppm are related to the entireformulation including the solvents.

The invention will now be described in more detail by reference to thefollowing examples, which are illustrative only and do not limit thescope of the present invention.

All process steps described above and below can be carried out usingknown techniques and standard equipment which are described in prior artand are well-known to the skilled person.

EXAMPLES Example 1

The substrate (2 cm² glass plates coated with PEDOT) was activated byheating for 10 minutes at 180° C. and used directly.

An OLED polymer ink was formulated by dissolving 0.5% by weight OLEDpolymer comprising structural units of the following formulae

in a weight ratio of 9% to 11% to 41% to 24% to 5% to 8% to 2% inpentamethylbenzene and gave a viscosity of 3.8 cp at 60° C.

The ink was printed with the Dimatix DMP 2800 printer (print head heatedto 60° C. plus heated glove) onto the substrate. 6 mm squares wereprinted with a drop spacing of 5, 10, 15, 20, 25, 30, 35 and 40 μm. Dropformation in the ink jet process was good as determined by visualizationusing a microscope illuminated by a strobe which effectively freezes thedroplets in flight.

After printing the ink on the substrate, further leveling was achievedby heating and cooling the film before removal of the solvent (53° C.for about 20 seconds).

Thereafter, the solvent was removed on a hot plate at 100° C. or undervacuum at 55° C.

An excellent OLED film was formed as observed via a fluorescence method(using a Nikon Eclipse E400 microscope).

Examples 2 to 4

Example 1 was repeated. However, 1% OLED polymer as mentioned in Example1 was dissolved in 2-methylnaphthalene, pentamethylbenzene and1,5-dimethylnaphthalene by heating the solvent to 80° C., respectively.

The compositions were processed as described in Example 1. However, thetemperature of the leveling step was about 2-5° C. above the meltingpoint of the solvent for approximately 20 seconds and the solventremoval was performed at 100° C.

Excellent OLED films were formed as observed via a fluorescence method(using a Nikon Eclipse E400 microscope).

Example 5

Example 1 was repeated. However, 1% OLED polymer as mentioned in Example1 was dissolved in 1,2,4,5-tetramethylbenzene by heating the solvent to85° C.

The composition was processed as described in Example 1. However, thetemperature of the leveling step was about 88° C. and the solventremoval was performed at 100° C.

An excellent OLED film was formed as observed via a fluorescence method(using a Nikon Eclipse E400 microscope).

Example 6

The substrate (2 cm² glass plates coated with PEDOT) was activated byheating for 10 minutes at 180° C. and used directly.

A printing ink was prepared by mixing a phosphorescent compoundaccording to formula 107

and a host material having the formula 147

in a weight ratio of 1:4 (phosphorescent compound 107: host material147) and dissolving the mixture obtained in pentamethylbenzene at 60° C.The concentration of both compounds in the solvent was about 1% byweight i.e. 0.2% of phosphorescent compound 107 and 0.8% of the hostmaterial 147.

The ink was printed with the Dimatix DMP 2800 printer (print head heatedto 60° C. plus heated glove) onto the substrate. 6 mm squares wereprinted with a drop spacing of 5, 10, 15, 20, 25, 30, 35 and 40 μm. Dropformation in the ink jet process was good as determined by visualizationusing a microscope illuminated by a strobe which effectively freezes thedroplets in flight.

After printing the ink on the substrate, further leveling was achievedby heating and cooling the film before removal of the solvent (53° C.for about 20 seconds). Thereafter, the solvent was removed on a hotplate at 100° C. or under vacuum at 55° C.

An excellent OLED film was formed as observed via a fluorescence method(using a Nikon Eclipse E400 microscope).

Example 7

Example 6 was repeated. However, glass substrates were prepared with aPEDOT layer as described above with a further layer of polymercomprising structural units of the following formulae.

The polymer was spin coated from toluene and dried for 5 minutes at 100°C. to obtain a hole transporting layer.

The ink as described in Example 6 was then printed and dried as aboveand provided the level film. This demonstrated an OLED layer stack ofglass, PEDOT (coated from water), hole transporting layer (coated froman organic solvent) and the SM OLED (printed from an organic solvent)where both the SM OLED and the polymer to obtain a hole transportinglayer are soluble in both solvent systems.

An excellent OLED film was formed as observed via a fluorescence method(using a Nikon Eclipse E400 microscope).

Examples 8 to 17

The mixture comprising a phosphorescent compound according to formula107 and a host material having the formula 147 as mentioned in Example 6in a weight ratio of 1:4 have been dissolved in 2-methylnaphthalene,1,5-dimethylnaphthalene (1,5-DMN), 5-indanol,1,2,3,4-tetrahydro-1-naphthol, 5,6,7,8-tetrahydro-2-naphthol,2-ethoxynaphthalene, 2-indanol, sulfolane, biphenyl and1,2,4,5-tetramethylbenzene at elevated temperatures (typically 10° C.above the melting point of the solvent). The concentration of bothcompounds 107 and 147 in the solvent was about 1% by weight.

These inks have been used to achieve printed films as described inExample 6. The quality of the films was good.

Examples 18 to 21

The mixture comprising a phosphorescent compound according to formula107 and a host material having the formula 147 as mentioned in Example 6in a weight ratio of 1:4 have been dissolved in 1:1 biphenyl:1,5-DMN,1:1 biphenyl:1,2,4,5-tetramethylbenzene, 2-methylnaphthalene and2-ethoxynaphthalene at elevated temperatures (typically 10° C. above themelting point of the solvent). The concentration of both compounds 107and 147 in the solvent was about 1% by weight.

These inks were printed on PEDOT coated glass and dried as in Example 6.However, the temperature of the leveling step was about 2-5° C. abovethe melting point of the solvent, and the solvent removal was performedat 100° C.

An excellent OLED film was formed as observed via a fluorescence method(using a Nikon Eclipse E400 microscope).

Example 22

Corning Eagle XG glass was washed in an ultrasonic methanol bath for 2minutes and then rinsed with methanol. Approximately 40 nm thick silvergate electrodes were evaporated. A UV curable dielectric layer of adielectric material Lisicon™ D207 (available from Merck KGaA) was spunon top of the OSC layer on the device and annealed at 120° C. for 1minutes to give a dry dielectric film of approximately 1 micron thick.The dielectric layer was then crosslinked by UV curing under 365 nmwavelength late, a total UV dose of 2.6 Jcm⁻².

Approximately 40 nm thick silver source drain electrodes were evaporatedwith an inter-digitated geometry of 1000 p wide and 50 p long.

The electrodes were treated with a reactive washing solution Lisicon™M001 (available from Merck KGaA) SAM treatment by spin coating fromisopropyl alcohol rinsed off with isopropyl alcohol and then dried onthe spin coater.

An OSC formulation was prepared by dissolving of 1.33 parts of acompound of formula M2 and 0.67 parts α-methylstyrene inpentamethylbenzene filtering the solution through a 0.45 μm PTFEcartridge filter.

In formula M2 one of Y¹ and Y² denotes —CH═ or ═CH— and the otherdenotes —S— and one of Y³ and Y⁴ denotes —CH═ or ═CH— and the otherdenotes —S—.

The OSC formulation was then printed using a Dimatix DMP2831 ink-jetprinter. The cartridge and head were heated to above the melting pointof the solvent (pentamethylbenzene). Each device was individuallyprinted over the source/drain electrodes. The resulting print was warmedto 52° C. to allow the ink to reflow, this was then placed in a bell jarwith no heat and the pressure was reduced to 5 mbar and left for 20minutes, in order to remove solvent.

Analysis of the device performance is then undertaken using an Agilent4155C semiconductor parameter analyzer, measuring the source and draincurrent and gate current as a function of the gate voltage (transistorcharacteristics). The charge carrier mobility is calculated by knownmethods, as disclosed for in US 2007/0102696 A1.

The transistor characteristic and the linear and saturation mobility ofthe device are depicted in FIG. 5. The device has a mobility (linear0.01 cm²/Vs, saturation 0.02 cm²/Vs) and good on/off ratio (10⁴). Thetransistor characteristics are very good.

The data show that the ink according to the present invention can beprinted using Ink-jet printing techniques, and can also generate workingtransistor devices that demonstrate both acceptable mobility and a goodon/off ratio.

1-17. (canceled)
 18. A composition comprising one or more organicsemiconducting compounds (OSC), and one or more organic solvents,wherein said composition is solid at a temperature of 25° C. and fluidat a higher temperature, preferably at 200° C., and the boiling point ofthe solvent is at most 400° C.
 19. The composition according to claim18, wherein said composition comprises a surface tension in the range of25 mN/m to 45 mN/m at 10° C. above the melting point of the solventhaving the highest boiling point.
 20. The composition according to claim18, wherein the composition comprises a viscosity in the range of 0.25to 100 mPas at 10° C. above the melting point of the solvent having thehighest boiling point.
 21. The composition according to claim 18,wherein said organic solvent comprises an aromatic and/or heteroaromaticcompound having a molecular weight of at least 120 g/mol.
 22. Thecomposition according to claim 18, wherein said organic solventcomprises a naphthalene compound, a benzene compound, a pyridinecompound, a pyrazine compound or a pyrazole compound having a molecularweight of at least 120 g/mol.
 23. The composition according to claim 18,wherein said solvent is a mixture, which comprises at least a benzenecompound, a naphthalene compound, a sulfolane compound, a sulfonecompound or an alcohol compound.
 24. The composition according to claim18, wherein said composition comprises at least one inert binder. 25.The composition according to claim 18, wherein the organicsemiconducting compound is an organic light emitting material and/orcharge transporting material.
 26. The composition according to claim 18,wherein the organic semiconducting compound is a compound selected fromthe following formulae

wherein n is an integer >1, R on each occurrence identically ordifferently denotes H, F, Cl, Br, I, CN, a straight-chain, branched orcyclic alkyl group having from 1 to 40 C atoms, in which one or more Catoms are optionally replaced by O, S, O—CO, CO—O, O—CO—O, CR⁰═CR⁰ orC≡C such that O- and/or S-atoms are not linked directly to each other,and in which one or more H atoms are optionally replaced by F, Cl, Br, Ior CN, or denotes an aryl or heteroaryl group having from 4 to 20 ringatoms that is unsubstituted or substituted by one or more non-aromaticgroups R^(s), and wherein one or more groups R may also form a mono- orpolycyclic aliphatic or aromatic ring system with one another and/orwith the ring to which they are attached, R^(s) on each occurrenceidentically or differently denotes F, Cl, Br, I, CN, Sn(R⁰⁰)₃, Si(R⁰⁰)₃or B(R⁰⁰)₂ a straight-chain, branched or cyclic alkyl group having from1 to 25 C atoms, in which one or more C atoms are optionally replaced byO, S, O—CO, CO—O, O—CO—O, CR⁰═CR⁰, C≡C such that O- and/or S-atoms arenot linked directly to each other, and in which one or more H atoms areoptionally replaced by F, Cl, Br, I or CN, or R^(s) denotes an aryl orheteroaryl group having from 4 to 20 ring atoms that is unsubstituted orsubstituted by one or more non-aromatic groups R^(s), and wherein one ormore groups R^(s) may also form a ring system with one another and/orwith R, R⁰ on each occurrence identically or differently denotes H, F,Cl, CN, alkyl having from 1 to 12 C atoms or aryl or heteroaryl havingfrom 4 to 10 ring atoms, R⁰⁰ on each occurrence identically ordifferently denotes H or an aliphatic or aromatic hydrocarbon grouphaving from 1 to 20 C atoms, wherein two groups R⁰⁰ may also form a ringtogether with the hetero atom (Sn, Si or B) to which they are attached,r is 0, 1, 2, 3 or 4, s is 0, 1, 2, 3, 4 or
 5. 27. The compositionaccording to claim 18, wherein the organic semiconducting compound is acompound of the following formula

wherein R¹, R², R³, R⁴, R⁷, R⁸, R⁹, R¹⁰, R¹⁵, R¹⁶, R¹⁷ eachindependently are the same or different and each independentlyrepresents: H; an optionally substituted C₁-C₄₀ carbyl or hydrocarbylgroup; an optionally substituted C₁-C₄₀ alkoxy group; an optionallysubstituted C₆-C₄₀ aryloxy group; an optionally substituted C₇-C₄₀alkylaryloxy group; an optionally substituted C₂-C₄₀ alkoxycarbonylgroup; an optionally substituted C₇-C₄₀ aryloxycarbonyl group; a cyanogroup (—CN); a carbamoyl group (—C(═O)NH₂); a haloformyl group(—C(═O)—X, wherein X represents a halogen atom); a formyl group(—C(═O)—H); an isocyano group; an isocyanate group; a thiocyanate groupor a thioisocyanate group; an optionally substituted amino group; ahydroxy group; a nitro group; a CF₃ group; a halo group; or anoptionally substituted silyl group; and A represents Silicon orGermanium; and wherein independently each pair of R¹ and R², R² and R³,R³ and R⁴, R⁷ and R⁸, R⁸ and R⁹, R⁹ and R¹⁰, R¹⁵ and R¹⁶, and R¹⁶ andR¹⁷ is optionally cross-bridged with each other to form a C₄-C₄₀saturated or unsaturated ring, which saturated or unsaturated ring isoptionally intervened by an oxygen atom, a sulphur atom or a group ofthe formula —N(R^(a))—, wherein R^(a) is a hydrogen atom or ahydrocarbon group, or is optionally substituted; and wherein one or moreof the carbon atoms of the polyacene skeleton is optionally substitutedby a heteroatom selected from the group consisting of N, P, As, O, S, Seand Te.
 28. The composition according to claim 18, wherein organicsemiconducting compound is an organic phosphorescent compound whichemits light and in addition contains at least one atom having an atomicnumber greater than
 38. 29. Composition according to claim 28, whereinthe phosphorescent compounds are compounds of formulae (1) to (4):

where DCy is, identically or differently on each occurrence, a cyclicgroup which contains at least one donor atom, preferably nitrogen,carbon in the form of a carbene or phosphorus, via which the cyclicgroup is bonded to the metal, and which may in turn carry one or moresubstituents R¹⁸; the groups DCy and CCy are connected to one anothervia a covalent bond; CCy is, identically or differently on eachoccurrence, a cyclic group which contains a carbon atom via which thecyclic group is bonded to the metal and which may in turn carry one ormore substituents R¹⁸; A is, identically or differently on eachoccurrence, a monoanionic, bidentate chelating ligand; R¹⁸ areidentically or differently at each instance, and are F, Cl, Br, I, NO₂,CN, a straight-chain, branched or cyclic alkyl or alkoxy group havingfrom 1 to 20 carbon atoms, in which one or more nonadjacent CH₂ groupsis optionally replaced by —O—, —S—, —NR¹⁹—, —CONR¹⁹—, —CO—O—, —C═O—,—CH═CH— or —C≡C—, and in which one or more hydrogen atoms is optionallyreplaced by F, or an aryl or heteroaryl group which has from 4 to 14carbon atoms and is optionally substituted by one or more nonaromaticR¹⁸ radicals, and a plurality of substituents R¹⁸, either on the samering or on the two different rings, may together in turn form a mono- orpolycyclic, aliphatic or aromatic ring system; and R¹⁹ are identicallyor differently at each instance, and are a straight-chain, branched orcyclic alkyl or alkoxy group having from 1 to 20 carbon atoms, in whichone or more nonadjacent CH₂ groups is optionally replaced by —O—, —S—,—CO—O—, —C═O—, —CH═CH— or —C≡C—, and in which one or more hydrogen atomsis optionally replaced by F, or an aryl or heteroaryl group which hasfrom 4 to 14 carbon atoms and is optionally substituted by one or morenonaromatic R¹⁸ radicals.
 30. The composition according to claim 29,wherein A is, identically or differently on each occurrence, and is adiketonate ligand.
 31. The composition according to claim 18, whereinthe composition comprises a host material.
 32. The composition accordingto claim 18, wherein the composition comprises at least one wettingagent.
 33. A coating or printing ink for the preparation of organicelectronic devices which comprises the composition according to claim18.
 34. A process of preparing an organic electronic (OE) device,comprising the steps of a) depositing the composition according to claim18 onto a substrate to form a film or layer, b) removing the solvent(s).35. An organic electronic device prepared from the composition accordingto claim
 18. 36. The OE device according to claim 33, wherein the deviceis an organic light emitting diode (OLED), an organic field effecttransistor (OFET) or an organic photovoltaic (OPV) device.